<template>
  <div class="file-upload">
    <div class="upload-area" :class="{ 'is-dragover': drag && isDragOver }" v-on="events">
      <slot v-if="isUploading" name="loading">
        <button disabled>正在上传</button>
      </slot>
      <slot name="uploaded" v-else-if="lastFileData && lastFileData.loaded" :uploadedData="lastFileData.data">
        <button>点击上传</button>
      </slot>
      <slot v-else name="default">
        <button>点击上传</button>
      </slot>
    </div>

    <input ref="fileInput" type="file" :style="{ display: 'none' }" @change="handleFileChange" />

    <ul :class="`upload-list upload-list-${listType}`" v-if="showUploadList">
      <li :class="`uploaded-file upload-${file.status}`" v-for="file in filesList" :key="file.uid">
        <img v-if="file.url && listType === 'picture'" class="upload-list-thumbnail" :src="file.url" :alt="file.name" />
        <span v-if="file.status === 'loading'" class="file-icon"><LoadingOutlined /></span>
        <span v-else class="file-icon"><FileOutlined /></span>
        <span class="filename">{{ file.name }}</span>
        <span class="delete-icon" @click="removeFile(file.uid)"><DeleteOutlined /></span>
      </li>
    </ul>
  </div>
</template>

<script lang="ts">
import { defineComponent, reactive, ref, computed, PropType } from "vue";
import { DeleteOutlined, LoadingOutlined, FileOutlined } from "@ant-design/icons-vue";
import axios from "axios";
import { v4 as uuidv4 } from "uuid";
import { last } from "lodash-es";
type UploadStaus = "ready" | "loading" | "success" | "error";
type FileListType = "picture" | "text";
type CheckUpload = (file: File) => boolean | Promise<File>;
export interface UploadFile {
  uid: string;
  size: number;
  name: string;
  status: UploadStaus;
  raw: File;
  resp?: any;
  url?: string;
}

export default defineComponent({
  components: {
    DeleteOutlined,
    LoadingOutlined,
    FileOutlined,
  },
  props: {
    action: {
      type: String,
      required: true,
    },
    beforeUpload: {
      type: Function as PropType<CheckUpload>,
    },
    drag: {
      type: Boolean,
      default: false,
    },
    autoUpload: {
      type: Boolean,
      default: true,
    },
    listType: {
      type: String as PropType<FileListType>,
      defualt: "text",
    },
    showUploadList: {
      type: Boolean,
      default: true,
    },
  },
  emits: ["success", "error", "change"],
  setup(props, { emit }) {
    const fileInput = ref<null | HTMLInputElement>(null);
    const filesList = ref<UploadFile[]>([]);
    const isDragOver = ref(false);
    const isUploading = computed(() => {
      return filesList.value.some((file) => file.status === "loading");
    });
    const lastFileData = computed(() => {
      const lastFile = last(filesList.value);
      if (lastFile) {
        return {
          loaded: lastFile.status === "success",
          data: lastFile.resp,
        };
      }
      return false;
    });
    const removeFile = (id: string) => {
      filesList.value = filesList.value.filter((file) => file.uid !== id);
    };

    const triggerUpload = () => {
      if (fileInput.value) {
        fileInput.value.click();
      }
    };
    const postFile = (readyFile: UploadFile) => {
      const formData = new FormData();
      formData.append(readyFile.name, readyFile.raw);
      readyFile.status = "loading";
      axios
        .post(props.action, formData, {
          headers: {
            "Content-Type": "multipart/form-data",
          },
        })
        .then((resp) => {
          readyFile.status = "success";
          readyFile.resp = resp.data;
          emit("success", {
            resp: resp.data,
            file: readyFile,
            list: filesList.value,
          });
        })
        .catch((e: any) => {
          readyFile.status = "error";
          emit("error", { error: e, file: readyFile, list: filesList.value });
        })
        .finally(() => {
          if (fileInput.value) {
            fileInput.value.value = "";
          }
        });
    };
    // addFileToList
    const addFileToList = (uploadedFile: File) => {
      const fileObj = reactive<UploadFile>({
        uid: uuidv4(),
        size: uploadedFile.size,
        name: uploadedFile.name,
        status: "ready",
        raw: uploadedFile,
      });
      if (props.listType === "picture") {
        try {
          // 内层URL
          fileObj.url = URL.createObjectURL(uploadedFile);
        } catch (err) {
          console.error("upload File error", err);
        }

        // base64
        /* const fileReader = new FileReader();
        fileReader.readAsDataURL(uploadedFile);
        fileReader.addEventListener("load", () => {
          fileObj.url = fileReader.result as string;
        }); */
      }
      filesList.value.push(fileObj);
      if (props.autoUpload) {
        postFile(fileObj);
      }
    };
    const beforeUploadCheck = (files: null | FileList) => {
      if (files) {
        const uploadedFile = files[0];
        if (props.beforeUpload) {
          const result = props.beforeUpload(uploadedFile);
          if (result && result instanceof Promise) {
            result
              .then((processedFile) => {
                if (processedFile instanceof File) {
                  addFileToList(processedFile);
                } else {
                  throw new Error("beforeUpload Promise should return File object");
                }
              })
              .catch((e) => {
                console.error(e);
              });
          } else if (result === true) {
            addFileToList(uploadedFile);
          }
        } else {
          addFileToList(uploadedFile);
        }
      }
    };
    const uploadFiles = () => {
      filesList.value.filter((file) => file.status === "ready").forEach((readyFile) => postFile(readyFile));
    };

    let events: { [key: string]: (e: any) => void } = {
      click: triggerUpload,
    };
    const handleFileChange = (e: Event) => {
      const target = e.target as HTMLInputElement;
      beforeUploadCheck(target.files);
    };
    const handleDrag = (e: DragEvent, over: boolean) => {
      e.preventDefault();
      isDragOver.value = over;
    };
    const handleDrop = (e: DragEvent) => {
      e.preventDefault();
      isDragOver.value = false;
      if (e.dataTransfer) {
        beforeUploadCheck(e.dataTransfer.files);
      }
    };
    if (props.drag) {
      events = {
        ...events,
        dragover: (e: DragEvent) => {
          handleDrag(e, true);
        },
        dragleave: (e: DragEvent) => {
          handleDrag(e, false);
        },
        drop: handleDrop,
      };
    }
    return {
      fileInput,
      handleFileChange,
      isUploading,
      filesList,
      removeFile,
      lastFileData,
      isDragOver,
      events,
      uploadFiles,
    };
  },
});
</script>

<style lang="scss">
.upload-list {
  margin: 0;
  padding: 0;
  list-style-type: none;
}
.upload-list li {
  transition: all 0.5s cubic-bezier(0.55, 0, 0.1, 1);
  font-size: 14px;
  line-height: 1.8;
  margin-top: 5px;
  box-sizing: border-box;
  border-radius: 4px;
  min-width: 200px;
  position: relative;
  &:first-child {
    margin-top: 10px;
  }
  .upload-list-thumbnail {
    vertical-align: middle;
    display: inline-block;
    width: 70px;
    height: 70px;
    position: relative;
    z-index: 1;
    background-color: #fff;
    object-fit: cover;
  }
  .file-icon {
    svg {
      margin-right: 5px;
      color: rgba(0, 0, 0, 0.45);
    }
  }
  .filename {
    margin-left: 5px;
    margin-right: 40px;
  }
  &.upload-error {
    color: #f5222d;
    svg {
      color: #f5222d;
    }
  }
  .file-status {
    display: block;
    position: absolute;
    right: 5px;
    top: 0;
    line-height: inherit;
  }
  .delete-icon {
    display: none;
    position: absolute;
    right: 7px;
    top: 0;
    line-height: inherit;
    cursor: pointer;
  }
  &:hover {
    background-color: #efefef;
    .file-status {
      display: none;
    }
    .delete-icon {
      display: block;
    }
  }
}
</style>
